How do you trust someone that lied over and over in the past and hurt you so deeply?

How do you trust again when the 2 of us were supposed to be FRIENDS, but he lied and hid every gf from me instead of just saying that he met someone. If we were FRIENDS you think he would just be honest instead of lying over and over.

How do you trust again after he stood there screaming at you that he was working on himself and he didn't want anyone in his life because he wanted to be a mentor at Church and his schooling and Church were the most important things in his life, but he was only being a mentor to get the mommy into bed?

How do you trust again after being thrown to the side 4 different times as soon as he finds a gf? Our friendship completely ends where I'm blocked and he refuses to speak or even tell me why he disappeared.

He wants to know what he can do to earn my trust being that his last gf cheated and lied and he was given a dose of his own medicine and didn't like how it felt. "I now see how it feels. I now know how all the girls felt and it sucks"

The last girl he was with that cheated he said he was deeply in love with. He was only with her 2 and a half months so how was he deeply in love?

Is there a way he can earn back the trust?

You tell me!